Master list of 65+ proven mods for increasing MPG

[Daox]

Acetone doesn't work. However, keeping your injectors and engine clean does (which is normally why you see a benefit from running acetone). Friction modifiers do work, it also goes by another name, synthetic oil. Anything else that isn't certified by labs that do oil work continuously isn't worth putting in an engine IMO. As explained above insulation around your O2 sensor doesn't work either.

[SOUL-DRIFTER]

I did not do tests to verify the 02 thingy. I will.
The acetone I have tested and retested and continually see a difference.
I have always used low viscosity synthetic oil. Always a wise choice.
I have also used other friction reducers and have had very noticable results from them.
You must keep in mind that what will work for one vehicle does not automatically mean it will work in all vehicles, and vice versa. I have seen this many times.
Ive been a mechanic for almost 50 years.

[Frank Lee]

You might want to search here for instructions on how to conduct a proper test.

[SOUL-DRIFTER]

I know how to do proper tests.
I have read a thread here on it.
Road tests are not the same as a scientific test however they can give a general idea whether or not something works.
I have seen many gas saving devices and claims. Most are B.S. but some have a logical base of science by which they MAY work. And occassionally some do.
I have heard many good claims with magnets but with test after test I have seen nothing for results.
I do not always go by what people say about something.
Most of the time it is best to test an idea for yourself to see the results.

Do any of you recall when special pills were being sold that claimed it would boost fuel mileage?
Well, I had to give them a test. I have 3 different vehicles and believe it or not and as much as I hate to admit it, those pills did help the fuel economy in one of them. In fact after testing them repeatedly in my Chrysler Town & Country I got an average of 4mpg better. But in my Aspire and Chevy truck there was absolutely no difference at all.
I keep a constant log book of my fuel mileage in my vehicles so I can keep constant track of any changes.

[Daox]

The 65+ mods list is reserved for proven modifications. We here have never seen any testing to show that acetone improves mileage, thus it is not on the list. The same goes for any other mods you've mentioned that aren't on the list. If you want to take the time to do the testing to get something on the list go for it.

[SOUL-DRIFTER]

Fair enough.
But what about a cars finish?
Hasn't it been proven that a good wax job over a dirty dingy surface will reduce wind drag?

[Daox]

We've never seen any scientific testing that even tested it. If you read up on aerodynamics (Hucho wrote the bible on it) you'll know that surface friction contributes a very small percentage of a vehicle's total drag. I doubt even testing in a wind tunnel could differentiate between a freshly waxed vs dirty car.

[SOUL-DRIFTER]

Here is an interesting article on wind drag...
Re: Does a well waxed automobile get measurably better mileage than unwaxed?

•from Clarence Chang, Ph.D., NASA Lewis Research Center, Cleveland, Ohio:
Below 35 mph (there about) the skin drag is dominant. Above that speed, the pressure drag dominates. Skin drag is linear with speed. Pressure drag is proportional to speed square. Polishing the painted surface won't do anything for the pressure drag, only the skin drag.
However, the turbulent drag from the various protrusions are much more dominant than the skin drag. For example, if you enclose the bottom of the car in a smooth flat skin (that is, no exhaust pipe and other stuff exposed), you can easily get the drag coefficient to drop another 20%. The drag coefficient on a typical car is about 0.35. 20% of that is alot. If you open the windows, for example, you can easily increase the drag 5 to 10% or so.
Making the surface smooth only works for bodies with very low Cd, say in the neighborhood of below 0.1. There are several easy ways to reduce drag. You can enclose the bottom of cars with a smooth skin, but of course the shops don't like it since you'd have to take the panels off to work on the car. If however, you lower the body so that the distance between the floor pan and the ground is closer, drag goes down too. You can also put an air dam in the front of the car to route the air around instead of letting it go under the car. That works too.

[MetroMPG]

The key part of that quote:

Making the surface smooth only works for bodies with very low Cd, say in the neighborhood of below 0.1.

The Cd of typical cars ranges from 0.25 to 0.35. So worrying about waxing a car for fuel-saving isn't justified.

[SOUL-DRIFTER]

But...

Below 35 mph (there about) the skin drag is dominant.

What about city driving then?